1. Field of the Invention
This invention relates to a pipe frame used for wiper apparatuses of the motor vehicles, which is provided with a pivot holder formed in a united one body.
2. Description of the Prior Art
As a conventional pipe frame of the wiper apparatus formed with a pivot holder in a united one body, there has been known a pipe frame which is provided with the pivot holder formed through outsert moulding of resin at a plate-like portion formed on a part of the pipe frame.
However, in the aforementioned pipe frame, it is necessary to make a hole in the plate-like portion of the pipe frame in order to form a pivot shaft-hole of the pivot holder for supporting a pivot shaft rotatably, therefore the pressworked plate-like portion becomes lower in the mechanical strength and the pipe frame is short in the strength on the whole. Consequently, there is a problem in that there is the possibility that the pivot holder may be dislocated and have an influence on the movements of the wiper in a case where the pipe frame deflects. Further in a case where the pivot holder is formed on the pipe frame through outsert moulding of resin, the resin material sometimes flows into a hollow of the pipe frame through a space opening at the hole in the plate-like portion of the pipe frame, and there is another problem in that the resin material becomes wasteful in such the case.
Therefore, this invention is made in view of the aforementioned problems of the prior art, and it is an object to provide a pipe frame for the wiper apparatus which is excellent in the mechanical strength and possible to be obtained without waste of the resin material.
The pipe frame for the wiper apparatus according to this invention is characterized by comprising a pipe body with a hollow, a plate portion formed by compressing the pipe body, crush-projections formed on both sides of the plate portion, a hollow cylindrical protrusion formed on the plate portion, and a pivot holder formed through outsert moulding of resin around about the plate portion of the pipe body and provided with a pivot shaft hole communicated with the hollowness of the cylindrical protrusion of the plate portion.
In the pipe frame according to this invention, the pivot holder unites with the pipe body around about the plate portion of the pipe body provided with the crush-projections and the hollow cylindrical protrusion through the outsert moulding of resin, therefore the plate portion of the pipe frame is improved in the mechanical strength by forming the crush-projections on the both sides, thereof and forming the hollow cylindrical protrusion thereon as compared with the conventional pipe frame having the plate-like portion which is formed through the simple press working and provided with the hole for supporting the pivot shaft. Furthermore, the hollow cylindrical protrusion is formed protrudingly through, for example, the press working on the plate portion formed by compressing the pipe body, therefore the inner wall of the hollow cylindrical protrusion is stretched from the surface of he plate portion onto the reverse side and isolates the hollow of the pipe body, and the resin material does not flow into the hollow of the pipe body through a gap formed between walls of the plate portion formed by compressing the pipe body.